1. Field of the Invention
The present invention relates to an electric junction box. More particularly the present invention is intended to make the electric junction box compact by improving a watertight construction thereof.
2. Description of the Related Art
As the conventional watertight construction of the electric junction box mounted on vehicles and the like, the construction shown in Japanese Patent Application Laid-Open No. 9-308053 (patent document 1) is known. More specifically, as shown in
FIG. 12, the electric junction box 1 includes a case body 2 in which the bus bar 6 and the fuse 7 are mounted, the upper cover 3 mounted on the upper surface of the case body 2 to cover the upper surface thereof, and a lower cover 4 mounted on the lower surface of the case body 2 to cover the lower surface thereof. The case body 2 and the upper cover 3 are locked to each other with a locking portion 5a. The case body 2 and the lower cover 4 are locked to each other with a locking portion 5b. The rib 3b is formed along the inner surface of the entire peripheral wall 3a of the upper cover 3 to form the electric junction box 1 as a double-wall construction, and the peripheral wall 2a of the case body 2 is fitted between the peripheral wall 3a and the rib 3b to thereby construct the entire electric junction box 1 to have a watertight construction.
In the above-described construction, the double-wall construction is formed along the entire peripheral wall 3a of the upper cover 3. Thus a large space is required to form the rib 3b, which causes the electric junction box 1 to have a large outer configuration. This construction is unfit for the demand for miniaturization of the electric junction box and causes the layout to be bad. The outermost peripheral part of the electric junction box 1 constructs the watertight construction thereof. Thus the watertight performance is readily influenced by the configuration of the electric junction box 1. If the electric junction box 1 has a long side, the peripheral wall of the long side and the rib are liable to warp and shrink. Thus it is difficult for the electric junction box 1 to display constant performance and allow a particular region inside the electric junction box 1 to secure high watertight performance.
Patent document 1: Japanese Patent Application Laid-Open No. 9-308053